In an electrical assist steering system, it is imperative that the steering power assist motor remain inactivated when the steering wheel is not being turned. Conversely, the instant the steering wheel is turned, even slightly in either direction of rotation, the power assist motor should become energized to assist in the steering of the vessel or vehicle, to the left or to the right.
The present invention contemplates a steering system wherein the steering power assist motor is speed and direction responsive to electric signals fed thereinto. More specifically, the electric signals are generated by means of pressure being exerted against wafers or film of a suitable material preferably polyvinylidene fluoride, which has been prepared by known methods to be highly piezoelectric. These electric signals are generated in response to rotation of the steering wheel as well as the speed of rotation thereof. Available torque of the power assist motor is substantially inversely proportional to the rpm of the engine which is propelling or driving the vessel or vehicle.
While the present invention will be described hereinafter with reference to marine vessels, it is not intended that the invention be so limited. The piezoelectric elements of the sensor units are referred to hereinafter as wafers, films, or elements.